Yellow Dragon Disease Newest Threat To FL Citrus - Worse Than Canker - NYT

After battling intense hurricane seasons and plant-destroying citrus canker, Florida citrus growers now have another threat to deal with. A plant condition from China known as yellow dragon disease or citrus greening has been found in southeast Florida and appears to be spreading, agricultural authorities say.

The bacterium causing the disease, also known by its Chinese name huanglongbing, is spread by a small, winged insect called the Asian citrus psyllid. The bug was first seen in the state in 1998, but the disease was not seen until August, when it was found in Homestead, south of Miami.

Although the disease poses no direct health threat to humans, it can be devastating to citrus trees and the industry, the authorities said. An infected tree produces discolored fruit with a bitter, medicinal taste, Richard Miranda, a spokesman for the state's Department of Agriculture, said yesterday. "Once the insect feeds on an infected tree, it will be a carrier of the disease for life," Mr. Miranda said. "It will spread to other trees. That's the real danger here."

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He said citrus greening was much worse than citrus canker because citrus canker led to the death of the tree by compromising its immune system. Citrus greening directly kills the tree through its vascular system, and Mr. Miranda said it was much more difficult to find. "Citrus canker has very distinct symptoms and lesions," he said. "Citrus greenery can look like a nutrient-deficient tree, of which we have many."

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http://www.nytimes.com/2005/10/14/national/14citrus.html